单选题 A company has $30 million in debt outstanding with coupon rate of 15%. Currently the yield to maturity (YTM) on these bonds is 12%. If the firm"s tax rate is 30%, what is the company"s after-tax cost of debt?

A、 3.6%
B、 8.4%
C、 10.5%

【正确答案】 B

【答案解析】[解析] 税后债务成本是通过计算(1-t)k _d 而得到的，它等于厂商发行新的债券所应支付的利率k _d 减去发行债券所节省的税金支出tk _d ，从而有以下关系式：
税后债务成本=利率(YTM)-税金节省比率=k _d -tk _d =(1-t)k _d
在本题中，税后债务成本=(1-t)k _d =(1-30%)×12%=8.4%。